A. actinomycetemcomitans (Aa), a gram-negative bacterium, is the causative agent of localized aggressive periodontitis and other infections such as brain abscesses and infective endocarditis. The Tad secretion system in Aa constitutes a novel secretion system in bacteria and has been discovered in a variety of bacteria including significant pathogens. In Aa the Tad secretion system is encoded by 14-gene loci (tad). The ability to form strong biofilms and colonize surfaces is dependent on the tad loci. Furthermore, the Tad secretion system is an important virulence determinate in Aa. TadZ is a unique component of the Tad secretion system. Therefore, its function in this novel secretion system remains unknown. The role and function of TadZ in this secretion system will be explored. The experiments are directed at elucidated the function of TadZ and determining the cellular localization of TadZ. Standard fluorescence microscopy and biochemical techniques will used to determine if TadZ localizes to the cell pole. Lastly, interacting partners, ability to self-interact, and ATPase activity will be identified and tested. The studies will not only reveal the function of TadZ, but it will begin to reveal the structure and architecture of the Tad Secretion system.